You will often find us growing on rocks or dead coral. It's hard to find space to grow in on the reef, so we will also try to grow on live coral too! We are in competition with coral. If it weren't for all the animals that eat us, we would overgrow the coral and take over the reef.
We are a combination of many different types of algae: red, green, brown and blue-green. This diversity of algae is what makes us important; every creature on the reef either depends on us directly for their food or eats something that eats us!
We are a very important part of the reef. We are a community of different types of stringy and fleshy algae. We produce much of the food that is eaten on the reef, and we also provide a home for many of the small animals that live on the reef. Without us, life on the reef wouldn't be possible!
We don't have to eat because we make our own food! We make our food through a process called photosynthesis. During photosynthesis we take carbon dioxide and energy from the sun and convert that into sugar and oxygen. Photosynthesis takes place in organ-like parts in our cells called chloroplasts. Because we make our own food, we are producers.
We aren't in any danger, but we can be dangerous to the reef! If we grow too much then we could cover the coral, blocking the sunlight and killing it! This is happening in reefs where nutrients used to grow food on land end up in the ocean water. We use these nutrients to grow too quickly and threaten the other reef species.